Via FOXNews. No details yet. Developing…
update: As Michele notes in the comments, FOX has removed the breaking news banner from its web site (the banner linked to their general coverage with no specific details of arrests). Don’t know that they’ve issued a correction, but no one else has the story, so take this story with a grain of salt.
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update 2: AP has this (thanks to Matt)
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update 3: London police seem to be looking for all 4 bombers. So unless and until you hear differently, disregard the initial reports.

Fox took the breaking news alert and the link down. No one else has it.
I SMELL A COVER UP!!!!!
FWIW, the AP has this:
Two Arrested in London Subway, Bus Blasts
Spamword: take, as in take it with a grain of salt.
Jesus, I may never wash my monitor again!
Now if my name were only up in bright orange lights…
“I wouldn’t take the Tube now,” he said. “I’ll buy a bicycle or walk.”
Does Halliburton make bicycles?